Electric machines are frequently fitted with sensors so as to detect a rotor position. By way of example, one or multiple sensors are placed around a shaft of a rotor of the electric machine, said sensors being used to ascertain the angle of rotation of the rotor relative to a stator of the electric machine. These sensors can be embodied in particular so as to detect the position of a transmitter wheel that is coupled to a shaft of the rotor. Magnetic measuring principles are frequently used, wherein the transmitter wheel is embodied with a magnetic ring and the sensors can be embodied as Hall sensors, GMR sensors and the like.
Furthermore, it can be provided that the sensors are arranged on a circuit board and connected in an electrically conductive manner to a control unit of the electric machine by way of conductor tracks of the circuit board.
Electrically commutated electric machines are generally controlled so that a stator magnetic field is in advance of a rotor magnetic field by a position angle of 90° of the electric rotor position. In order to achieve particular operating modes, such as for example a field-weakening mode, it can be advantageous to set a so-called pilot angle by means of which the advancement of the stator magnetic field is greater than 90°. In simple motor systems, such a greater advancement is achieved by virtue of the fact that the sensors for the position detection are arranged about the rotational axis of the shaft offset in comparison to their arrangement without a pilot angle by a defined angle so that said sensors signal a position angle that lags behind the actual position angle.
By way of example, it is possible in the case of electric machines that are designed for operating in only one direction of rotation to use a pilot angle for increasing performance with a field-weakening mode. In the case of an electric machine that is to be operated in contrast in two directions of rotation, such a pilot angle is generally not provided in order to be able to achieve an identical performance capability of the electric machine for two directions of rotation. The associated different positioning of the sensors in or on the electric machine can lead to increased production costs.
It is therefore the object of the present disclosure to render it possible to embody an electric machine in a cost-effective manner as desired with or without a pilot angle or with different pilot angles.